Unauthenticated router crash via unchecked CGI parameter concatenation
Published Feb 23, 2026 · Updated Feb 23, 2026
Stack-based buffer overflow in Tenda FH1203 2.0.1.6 allows remote attackers to crash or reboot the router through the SetClientPrio CGI endpoint. formSetClientPrio passes unvalidated ip and mac parameters to modify_add_client_prio, where sprintf concatenates them into a 516-byte stack buffer without bounds checking. An unauthenticated crafted HTTP request with a nonzero op value and an oversized parameter is sufficient; service interruption is confirmed, while code execution is unconfirmed.
Summary
What happened
Stack-based buffer overflow in Tenda FH1203 2.0.1.6 allows remote attackers to crash or reboot the router through the SetClientPrio CGI endpoint. formSetClientPrio passes unvalidated ip and mac parameters to modify_add_client_prio, where sprintf concatenates them into a 516-byte stack buffer without bounds checking. An unauthenticated crafted HTTP request with a nonzero op value and an oversized parameter is sufficient; service interruption is confirmed, while code execution is unconfirmed.
The record
- CVE
- CVE-2025-69700
- Published
- Feb 23, 2026
- Updated
- Feb 23, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-121, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 23, 2026CVE publishedPublication date reported by the CVE source.
- Feb 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- SemVulLLM CVE-2025-69700 proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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